Previously, tapered ends on lugs of lead battery plates have been used for the snug fit and easy removal of battery connections, such as shown in Logan U.S. Pat. No. 417,055 issued Dec. 10, 1889, or for decoration as shown in Bender U.S. Pat. No. 915,063 issued Mar. 16, 1909, or for easy release from a mold such as the bevelled edges of the plate grid shown in Carlile U.S. Pat. No. 2,671,944 issued Mar. 16, 1954.
It is also known in cast-on procedures that the reduction of the mass of metal which is inserted into the molten metal decreases the thermoconductivity away from the molten metal such as taught in McMahan U.S. Pat. No. 2,332,330 issued Oct. 19, 1943.
However, for casting-on collectors or terminals to lead battery plates in an automatic machine, various methods have been employed to control the rate of solidification of the lead in the mold after the lugs have been inserted therein, so that they do not conduct too much heat away from the molten metal in the mold and solidify it too quickly, such as by the application of additional heat to the mold as taught in Galloway U.S. Pat. No. 2,454,052 issued Nov. 16, 1954, or by preheating the lugs before they are inserted into the mold as taught in Sabatino et al U.S. Pat. No. 3,253,306 issued May 31, 1966. Thus the known prior art machines required additional heat and the expenditure of more energy in order to produce an effective cast-on lead collector bar to lead battery plate grid lugs.